A VERY LOWPOWER FLASH AD CONVERTER BASED ON CMOSINVERTER CIRCUIT

1
A VERY LOW-POWER FLASH A/D CONVERTER BASED ON
CMOSINVERTER CIRCUIT

• Shih-Chang Hsia and Wen-Ching
  Lee
• Department of Computer and
  CommunicationEngineering,National Kaohsiung First
  University of Science and Technology, Kaohsiung,
  Taiwan, R.O.C.
• ?????
• ???????
• ??95662001
• ??3?12?

2
Abstract

• A/D converter (ADC) is a basic device in digital
  signal processing systems.
• Due to require many analog comparators, the chip
  complexity and power dissipation become very
  high.
• By adjusting the ratio of channel length and
  width of the CMOS inverters is various to detect
  input analog signal.

3
Threshold is dependent on the ßp and ßn
4
The transited point of 15 inverters
ZuLn/Wn ZpLp/Wp
5
The input and output of 4-bit ADC
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
6
Chip Feature of Proposed ADC chip
7
The architecture of proposed ADC chip
CMOS inverters
8
A two-step ADC architecture
MSB
LSB
Vin2 16(Vin-Vo(MSB))
9
Comparisons with other ADC Chips
10
The layout of the proposed ADC chip
11
Conclusions

• The great advantages are that the input capacitor
  can be been reduced and input impedance becomes
  very high.
• The reference voltage and resister can be saved.
• Comparison with other ADC core, this chip can
  achieve very low power dissipation and use small
  silicon area.
• The proposed 8-bit ADC chip can be applied on
  low-cost video systems.

12
References

• 1 D. A. Pucknell and K. Eshraghian, Basic
  VLSI design,
• Prentice Hall.3rd edition .
• 2 A. Stojcevski, H.P. Le, J. Singh and A.
  Zayegh, Flash
• ADC architecture, IEE Electronics Letters,
  vol.39, no.6,
• pp. 501-502, Mar. 2003.
• 3 C.W. Hsu and T.H. Kuo, 6 bit 500MHz flash
  A/D converter with new design techniques, IEE
  Proc. Circuits Devices Syst., vol.150, no. 5, pp.
  460-464, Oct. 2003.